Semiconductor substrate and method for manufacturing semiconductor device

ABSTRACT

Provided is a method for manufacturing a semiconductor device, which prevents waste generation from being caused peeling of films and prevents failure of peeling from being caused by waste due to peeling of films. A first semiconductor substrate is used which has a structure in which a peeling layer is not formed in a section subjected to a first dividing treatment, so that the peeling layer is not exposed at the end surface of a second semiconductor substrate when the second semiconductor substrate is cut out of the first semiconductor substrate. In addition, a supporting material is provided on a layer to be peeled of the second semiconductor substrate before the second semiconductor substrate is subjected to a second dividing treatment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention related to a semiconductor substrate and a methodfor manufacturing a semiconductor device with the use of thesemiconductor substrate.

It is to be noted that the semiconductor substrate in this specificationrefers to a substrate with a semiconductor element or a semiconductorcircuit, etc. formed thereon.

2. Description of the Related Art

In recent years, there has been a rapid increase in the demand forflexible semiconductor devices such as flexible electronic paper andsolar cells which is able to be placed on curved surfaces. Accordingly,the techniques for manufacturing flexible semiconductor devices havealso been attracting a high degree of attention all over the world.

As an example of techniques for manufacturing thin flexiblesemiconductor devices, a method for manufacturing a flexiblesemiconductor device has been proposed in which a thin film layer(hereinafter, abbreviated as a layer to be peeled) including thesemiconductor device formed on a glass substrate or the like is peeledfrom the substrate, and transferred to other flexible material, forexample, a plastic film (Patent Document 1).

[Reference]

-   Patent Document 1: Japanese Published Patent Application No.    2003-174153

SUMMARY OF THE INVENTION

Now then, for the purpose of peeling a layer to be peeled from asubstrate with the layer to be peeled formed (hereinafter, abbreviatedas a first semiconductor substrate) and transferring the layer to bepeeled onto a second substrate with the use of the technique in PatentDocument 1, it is desired as one of means for increasing the productionefficiency that the size of the first semiconductor substrate isincreased to form more semiconductor devices.

This means allows more flexible semiconductor devices to be manufacturedfrom the first semiconductor substrate.

However, with the increase in the size of the first semiconductorsubstrate, the problem of increased difficulty is caused in dealing withthe substrate during the peeling operation or after the peelingoperation.

Therefore, before the peeling operation, the first semiconductorsubstrate is preferably divided into a size which is easy to deal with(hereinafter, the divided first semiconductor substrates are eachabbreviated as a second semiconductor substrate).

However, the peeling layer, which is the technique described in PatentDocument 1, has intentionally reduced adhesion to the substrate.Therefore, if a dividing treatment is carried out to cut across asection with the peeling layer formed, the peeling layer section will beexposed at the divided surface, and peeling of films will be likely tobe caused from the exposed peeling layer section.

For this reason, waste caused by peeling of films generated from theexposed peeling layer section will adhere onto the layer to be peeledduring the dividing operation of in a step subsequent to the dividingoperation.

The waste adheres onto the layer to be peeled applies a local forcepartially to the substrate or locally causes a section to which a forceis less likely to be applied, when the layer to be peeled is peeled in asubsequent step. Thus, the problem will be more likely to be caused,such as the layer to be peeled partially cracked or unpeeled during thepeeling.

While the waste adhering onto the layer to be peeled is removed byadding cleaning such as pulsed jet cleaning (running-water typehigh-frequency ultrasonic cleaning), it will cause an extra productioncost.

In addition, even when the additional cleaning is carried out for theremoval of the waste, it is difficult to remove the waste adhering ontothe layer to be peeled completely.

The present invention has been made in view of the foregoing technicalbackground. Accordingly, an object of the present invention is toprovide a method for manufacturing a semiconductor device which preventswaste generation from being caused by peeling of films and preventsfailure of peeling from being caused by waste due to peeling of films.

In order to achieve the object mentioned above, the present invention isfocused on the positional relationship between a peeling layer and alayer to be peeled in a first semiconductor substrate. The firstsemiconductor substrate is configured to have a structure in which thepeeling layer is not formed in a section subjected to a dividingtreatment (hereinafter, abbreviated as a first dividing treatment), sothat the peeling layer is not exposed at the end surface of a secondsemiconductor substrate when the first semiconductor substrate issubjected to the first dividing treatment to extract the secondsemiconductor substrate. Thus, during the first dividing treatment andafter the dividing treatment, waste can be prevented from being causedby peeling of films from the section of the peeling layer.

In addition, a supporting material is provided on the layer to be peeledof the second semiconductor substrate before applying a dividingtreatment for exposing the peeling layer at the end surface of thesecond semiconductor substrate (hereinafter, abbreviated as a seconddividing treatment). Thus, waste caused by film peeling from the sectionof the peeling layer during the second dividing treatment and after thedividing treatment adheres onto the support material, rather thandirectly to the layer to be peeled. Therefore, the supporting materialserves as a buffer when the layer to be peeled is peeled from the secondsemiconductor substrate, and failure of peeling is prevented from beingcaused by waste due to peeling of films.

An aspect of the present invention is a method for manufacturing asemiconductor device, which is characterized in that it includes thesteps of: preparing a first semiconductor substrate with a plurality ofisland-shaped peeling layers formed on a substrate, and a layer to bepeeled formed for covering the peeling layers, the layer to be peeledincluding semiconductor circuits on the peeling layers; applying a firstdividing treatment to the first semiconductor substrate along a sectionincluding the substrate and the layer to be peeled in contact with eachother, thereby producing a second semiconductor substrate including oneisland-shaped peeling layer and the layer to be peeled covering thepeeling layer; providing a peelable supporting material on the layer tobe peeled, which is a surface of the produced second semiconductorsubstrate; applying a second dividing treatment to a section of thesecond semiconductor substrate, the section including the peeling layerand the layer to be peeled stacked, thereby exposing the peeling layerat an end surface of the second semiconductor substrate, and thenpeeling the substrate from the layer to be peeled; providing a basematerial on the surface of the layer to be peeled with the substrateseparated therefrom, with an adhesive material interposed therebetween;and peeling the peelable supporting material.

The aspect of the present invention allows for the manufacture of asemiconductor device which prevents waste generation from being causedby peeling of films from the section of the peeling layer and preventsfailure of peeling from being caused by waste due to peeling of films.

Furthermore, another aspect of the present invention is a method formanufacturing a semiconductor device, which is characterized in that itincludes the steps of: preparing a first semiconductor substrate with aplurality of island-shaped peeling layers formed on a substrate, and alayer to be peeled formed for covering the peeling layers, the layer tobe peeled including semiconductor circuits on the peeling layers;applying a first dividing treatment to the first semiconductor substratealong a section including the substrate and the layer to be peeled incontact with each other, thereby producing a second semiconductorsubstrate including one island-shaped peeling layer and the layer to bepeeled covering the peeling layer; providing a peelable supportingmaterial on the layer to be peeled, which is a surface of the producedsecond semiconductor substrate; applying a second dividing treatment toa section of the second semiconductor substrate, the section includingthe peeling layer and the layer to be peeled stacked, thereby exposingthe peeling layer at an end surface of the second semiconductorsubstrate, providing a peeling aid substrate on the surface of thesecond semiconductor substrate without the supporting material provided,with an adhesive material interposed therebetween, and then peeling thesubstrate from the layer to be peeled; providing a base materialsubstrate on the surface of the layer to be peeled with the substrateseparated therefrom, with an adhesive material interposed therebetween;and peeling the peelable supporting material.

The aspect of the present invention allows a peeling force to be appliedefficiently to the interface between the peeling layer and the layer tobe peeled when the first substrate is peeled, thereby allowing asemiconductor device which prevents failure of peeling from being causedby waste due to peeling of films to be manufactured with a high yield.

In addition, an aspect of the present invention is the method formanufacturing a semiconductor device, in which a material which may haveadherence decreased is used as the peelable supporting material.

The aspect of the present invention can prevent adverse effects on thesemiconductor circuit, such as film peeling and cracking, which arecaused when the supporting material is peeled.

In addition, an aspect of the present invention is the method formanufacturing a semiconductor device, in which as the peelablesupporting material, a material is used such that the adhesive force isstronger than the force required for peeling the first substrate fromthe layer to be peeled, and the adhesive force is weaker than theadhesive material.

The aspect of the present invention eliminates the need to carry out thetreatment for reducing the adhesive force of the supporting material,thus allowing a semiconductor device to be manufactured which preventsthe semiconductor circuit from being deteriorated.

In addition, an aspect of the present invention is the method formanufacturing a semiconductor device, in which a material which can bedissolved and removed by immersion in a solvent is used as the peelablesupporting material.

The aspect of the present invention eliminates the need to apply aphysical force for peeling the supporting material, thus allowing asemiconductor device to be manufactured which has no adverse effects onthe semiconductor circuit, such as film peeling and cracking which arelikely to be caused during the peeling of the supporting material.

It is to be noted that in this specification the semiconductor elementrefers to a semiconductor group which is not directly responsible forthe operation of the semiconductor device (for example, an evaluationelement which is used for partially or entirely evaluating theperformance of the semiconductor device), whereas the semiconductorcircuit refers to a semiconductor group which is directly responsiblefor the operation of the semiconductor device.

According to the present invention, a semiconductor device can beprovided which prevents waste generation from being caused by peeling offilms and prevents failure of peeling from being caused by waste due topeeling of films.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are diagrams illustrating a semiconductor substrateaccording to the present invention;

FIGS. 2A to 2D are diagrams illustrating a method for manufacturing asemiconductor substrate according to the present invention;

FIGS. 3A to 3E are diagrams illustrating a method for manufacturing thesemiconductor substrate;

FIGS. 4A to 4D are diagrams illustrating a method for manufacturing thesemiconductor substrate; FIGS. 5A to 5C are diagrams illustrating amethod for manufacturing the semiconductor substrate; and

FIGS. 6A to 6D are diagrams illustrating a method for manufacturing thesemiconductor substrate.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments will be described in detail with reference to the drawings.However, it is to be noted that the invention is not limited to thefollowing description, and it will be easily understood by those skilledin the art that various changes and modifications can be made withoutdeparting from the spirit and scope of the invention. Therefore, theinvention should not be construed as being limited to the description inthe following embodiments. It is to be noted that in the structuresaccording to the invention described below, the same portions orportions which have similar functions are denoted by the same referencenumerals through different drawings, and description of such portionswill not be repeated.

Embodiment 1

In the present embodiment, the structure of a first semiconductorsubstrate and the structure of a second substrate will be described withreference to FIGS. 1A to 1C, and a method for manufacturing asemiconductor device with the use of the second semiconductor substratewill be described with reference to FIGS. 2A to 2D and FIGS. 3A to 3E.It is to be noted that FIG. 1A is a top view of a first semiconductorsubstrate, and FIG. 1B is a cross-sectional view of FIG. 1A along analternate long and short dash line X1-X2, where a dashed line A1-A2, adashed line B1-B2, a dashed line C1-C2, and a dashed line D1-D2 indicatedividing lines for cutting a second substrate out of the firstsubstrate. In addition, FIG. 1C is the structure of a secondsemiconductor substrate cut out of the first substrate of FIG. 1A.

The first semiconductor substrate 100 has, on a substrate 101, aplurality of island-shaped peeling layers 102 formed and a layer to bepeeled 106 formed for covering the peeling layers 102. The layer to bepeeled 106 includes semiconductor circuits 104 as components forsemiconductor devices. It is to be noted that the semiconductor circuits104 are formed on the peeling layers 102.

It is to be notes that while the section with no peeling layers 102formed is present in a linear shape in FIG. 1A, the present invention isnot to be considered limited to this section. However, when the firstsemiconductor substrate is subjected to a first dividing treatment in asubsequent step, the section of the substrate 101 in contact with thelayer to be peeled 106 (the section with no peeling layers 102 formed)is subjected to the division. Therefore, also in order to carry out thefirst dividing treatment easily, the section of the substrate 101 incontact with the layer to be peeled 106 is desirably formed in a linearshape.

In addition, the distance between adjacent peeling layers 102 and thedistance between an end surface of the substrate 101 and the peelinglayer 102 are desirably made small to such an extent that the peelinglayer 102 is not exposed from any end surface of the divided substrate(that is, a second semiconductor substrate 110) after the dividingtreatment. These small distances can increase the formation area of thesemiconductor circuits 104 formed on the peeling layers 102, and thusform the semiconductor circuits efficiently.

The semiconductor circuit 104 has therein at least one semiconductorelement (for example, a thin film transistor, a diode, a resistor, acapacitative, etc.) formed, and the layer to be peeled 106 includes theplurality of semiconductor circuits 104.

It is to be noted that while the layer to be peeled 106 has therein onlythe semiconductor circuits 104 formed as components for semiconductorsubstrates in the present embodiment, an evaluation element (alsoreferred to as a TEG (Test Element Group)) for checking defective pointsor making performance evaluations on a semiconductor element (forexample, a semiconductor device) may be formed in a region betweenadjacent peeling layers 102 or in a region between an end surface of thesubstrate 101 and the peeling layer 102.

The region described above is left on the substrate 101 without beingpeeled after carrying out a peeling treatment in a subsequent step.Thus, even when the semiconductor element has a damaged point (forexample, a scratch caused by bringing a probe into contact with theevaluation element in order to measure electric characteristics) formed,adverse effects on the semiconductor circuits 104 can be suppressed,such as a crack caused and developed from the damaged point.

The substrate 101 is preferably rigid and has such heat resistance thatwithstands the formations of the peeling layers 102, semiconductorcircuits 104, and layer to be peeled 106, because the peeling layers 102and the layer to be peeled 106 including the semiconductor circuits 104are formed with the use of various types of film formation systems suchas a sputtering system and a CVD system. For example, a glass substrate,a quartz substrate, a metal substrate, a stainless steel substrate, asilicon wafer with an insulating layer formed on a surface thereof, etc.can be used.

It is to be noted that in this specification, a case will be describedin which a glass substrate which is easily increased in size andrelatively inexpensive is used as the substrate 101.

The peeling layers 102 can be formed from [1] a film containingnitrogen, oxygen, or hydrogen (for example, an amorphous silicon filmcontaining hydrogen, a hydrogen containing alloy film, an oxygencontaining alloy film, etc.), [2] a metal film (for example, tungsten(W), molybdenum (Mo), titanium (Ti), tantalum (Ta), niobium (Nb), nickel(Ni), cobalt (Co), zirconium (Zr), zinc (Zn), ruthenium (Ru), rhodium(Rh), palladium (Pd), osmium (Os), iridium (Ir), etc.), [3] an alloyfilm (an alloy of multiple types of metal elements, such as an alloy oftungsten and molybdenum), and [4] a metal film with a metal oxide formedon a surface thereof or an alloy film with a metal oxide formed on asurface thereof.

Among these films, the peeling layer 102 using [4] the metal film with ametal oxide formed on a surface thereof or the alloy film with a metaloxide formed on a surface thereof is desirable, because the adhesionbetween the peeling layer 102 and the layer to be peeled 106 isintentionally reduced so that the peeling layer 102 and the layer to bepeeled 106 can be peeled from each other by a physical means, and thepeeling operation can be thus carried out for short period of time andin safety.

Further, the method for forming a metal oxide at the surface of thepeeling layer 102 can include a method of thermally oxidizing thesurface of a metal film, a method of processing the surface of a metalfilm with oxygen or N₂O plasma, and a method of processing the surfaceof a metal film with a highly oxidative solution such as ozone water. Inaddition, other methods include a method adapted so that a metal oxideis formed at the interface between the layer to be peeled 106 and thepeeling layer 102 when the layer to be peeled 106 is formed. Forexample, when a film of silicon oxide is formed by a sputtering method,the surface of a metal film or an alloy film is oxidized during thedeposition of a silicon oxide on the surface of the metal film or alloyfilm. It is to be noted that a metal nitride film may be formed by aplasma treatment or a heat treatment, instead of the formation of ametal oxide on the surface of a metal film or an alloy film.

In addition, the peeling layer 102 may be a single layer, or may beformed from multiple layers.

The first semiconductor substrate 100 is subjected to the first dividingtreatment along the lines A1-A2, B1-B2, C1-C2, and D1-D2 in FIG. 1A,thereby providing the second semiconductor substrate 110. It is to benoted that the second semiconductor substrate 110 has the peeling layer102 which is not exposed from any end surface.

For this reason, waste generation can be suppressed which is caused bypeeling of films due to the first dividing treatment.

Next, a supporting material 200 is placed on the layer to be peeled 106of the second semiconductor substrate 110 (see FIG. 2A).

The supporting material 200 needs to have such adhesion that preventsthe supporting material 200 from being easily peeled from the layer tobe peeled 106 when the supporting material 200 is placed on the layer tobe peeled 106, and to have the property that the supporting material 200can be easily peeled from the layer to be peeled 106 after a basesubstrate is attached to the layer to be peeled 106 with an adhesivematerial interposed therebetween in a subsequent step. As this type ofmaterial, for example, a resin or the like can be used which can haveadherence decreased by applying a load such as ultraviolet irradiation,heat addition, or electric current.

It is to be noted that while the supporting material 200 is shown as asingle layer in FIG. 2A, examples of the supporting material 200 alsoinclude a supporting material which has a laminate structure. As thesupporting material which has a laminate structure, for example, atape-shaped material can be used which has a laminate of a resin and aplastic film, in which the resin can have adherence decreased byapplying a load such as ultraviolet irradiation, heat addition, orelectric current.

In this embodiment, a method for manufacturing a semiconductor device isdescribed for the case of using, as the supporting material 200, a resinwhich can have adherence decreased by ultraviolet irradiation.

Next, a second dividing treatment is applied to form dividing lines inthe section of the peeling layer and layer to be peeled stacked near theperipheral section of the substrate 101 (see FIG. 2B), and separate thesubstrate 101 outside the dividing lines from the second semiconductorsubstrate 110 (see FIG. 2C).

It is to be noted that examples of the second dividing treatmentinclude, for example, a method of pressing a blade with a sharp tip 202against the substrate to cut the substrate as shown in FIG. 2B.

It is to be noted that while the formation of dividing lines is carriedout from the rear surface (the side with no layer to be peeled formed)of the substrate 101 in the present embodiment, the present invention isnot to be limited to this embodiment. As long as the substrate 101 canbe separated without fail after the formation of dividing lines,dividing lines may be formed from the supporting material side.

When the second dividing treatment is carried out, waste (for example,extremely fine glass powder) is generated at the divided points.However, with the supporting material 200 formed on the layer to bepeeled 106, even if waste adheres onto the supporting material 200, alocal force applied to the layer to be peeled 106 can be relaxed by thesupporting material 200 when the substrate 101 is peeled in a subsequentstep. For this reason, cracking caused in the layer to be peeled 106 dueto waste and defective peeling can be suppressed.

Next, the supporting material 200 side of the substrate 101 is fixed toa fixing jig 204. In this state, an external force is applied to theinterface between the peeling layer 102 exposed at the end of thesubstrate and the layer to be peeled 106. This application of theexternal force causes one or both of the layer to be peeled 106 and thesubstrate 101 to undergo a deflection. As a result, a section of thesubstrate 101 peeled from the layer to be peeled 106 is formed partiallyor entirely at the substrate periphery with the peeling layer 102exposed.

It is to be noted that examples of the external force in the presentembodiment include, for example, a method of pressing a blade with asharp tip 205 against the interface between the peeling layer 102 andthe layer to be peeled 106 to apply a force as shown in FIG. 2D.

In addition, as for the fixing jig 204, examples include, for example, amethod (also referred to as a porous chuck) for placing an object to befixed on one surface of a porous pedestal with pores, and carrying outvacuuming from the other surface of the porous pedestal with pores,thereby fixing the object.

The implementation of this treatment can prevent cracking from beingcaused and developed at the substrate periphery with the peeling layer102 exposed, when the substrate 101 is peeled entirely from the layer tobe peeled 106 in the next step.

Next, with, as a starting point, the section with the layer to be peeled106 peeled by the treatment described above, the substrate 101 is peeledwholly from the layer to be peeled 106 (see FIG. 3A).

Next, the layer to be peeled 106 with the supporting material 200 formedis separated from the fixing jig 204, and a base material 302 is placedon the side of the layer to be peeled 106 opposite to the side with thesupporting material 200 formed, with an adhesive material 300 interposedtherebetween (see FIG. 3B).

The adhesive material 300 may be any material as long as the materialhas such an adhesive force that prevents the layer to be peeled 106 andthe base material 302 from being easily peeled from each other after thebase material 302 is placed on the layer to be peeled 106 with theadhesive material 300 interposed therebetween.

Further, for the base material 302, for example, glass substrates,silicon wafers, metal plates, various types of plastic substrates, etc.can be used, and preferably, it is desirable to use a flexible materialsuch as glass or a silicon wafer polished into a thin form, a metal thinfilm, various types of plastic films, prepreg (a structure of a fiberimpregnated with an organic resin).

It is to be noted that when a structure of a fiber impregnated with anorganic resin, such as prepreg, is used as the base material 302, theadhesive material 300 does not always have to be used because the basematerial 302 itself contains an adhesive material.

Next, the supporting material 200 is subjected to an adhesion-reducingtreatment 304 to reduce the adhesion of the supporting material 200 tosuch an extent that the supporting material 200 can be peeled easilyfrom the layer to be peeled 106 (see FIG. 3C). It is to be noted thatwhile a resin which can have adherence decreased by ultravioletirradiation is used as the supporting material 200 in the presentembodiment, the adhesion-reducing treatment 304 in FIG. 3C represents anultraviolet irradiation treatment.

It is to be noted that it is desirable to change the adhesion-reducingtreatment 304 appropriately depending on the type of the supportingmaterial used. For example, in the case of using, as the supportingmaterial 200, a material which has adhesion decreased by applying a heattreatment, the adhesion-reducing treatment 304 refers to a “heattreatment”.

Next, the supporting material 200 is peeled from the layer to be peeled106 (see FIG. 3D). Thus, a flexible semiconductor device 310 can bemanufactured where the layer to be peeled 106 with the semiconductorcircuit 104 formed therein responsible for the operation of thesemiconductor device is fixed to the base material 302 with the adhesivematerial 300 interposed therebetween (see FIG. 3E).

The use of the method described above can prevent waste generation frombeing caused by peeling of films from the peeling layer section duringthe first dividing treatment, and can prevent defective peeling frombeing caused by waste due to peeling of films from the peeling layersection during the second dividing treatment.

Thus, a flexible semiconductor device can be manufactured with a highyield.

Further, the present embodiment can be appropriately combined with anyof the other embodiments described in this specification.

Embodiment 2

In the present embodiment, in connection with the method formanufacturing a semiconductor device as described in Embodiment 1, amethod will be described with reference to FIGS. 4A to 4D for peelingthe substrate 101 in a simpler way from the layer to be peeled 106 withthe semiconductor circuit 104 formed therein responsible for theoperation of the semiconductor device.

First, as in the case of Embodiment 1, the second semiconductorsubstrate 110 is prepared, the supporting material 200 is formed on thelayer to be peeled 106, and the second dividing treatment is applied toform dividing lines in the section of the peeling layer and layer to bepeeled stacked near the peripheral section of the substrate 101, andseparate the section outside the dividing lines (see FIG. 4A).

Next, a peeling aid substrate 402 is placed on the surface of thesubstrate 101 with no layer to be peeled 106 formed, with an adhesivematerial 400 interposed therebetween (see FIG. 4B)

The adhesive material 400 may be any material as long as the materialhas such an adhesive force that prevents the substrate 101 and thepeeling aid substrate 402 from being easily peeled from each other.

As for the peeling aid substrate 402, when the peeling aid substrate 402is provided on the substrate 101 with the adhesive material 400interposed therebetween, at least a portion of the peeling aid substrate402 is not overlapped with the substrate 101 (protrudes outwardly fromthe end surface of the substrate 101) desirably.

It is to be noted that the material of the peeling aid substrate 402 isdesirably a strongly rigid material. For example, glass substrates,quartz substrates, metal substrates, stainless steel substrates, etc.can be used.

Next, the supporting material 200 is fixed to the fixing jig 204. Inthis state, an external force is applied to the portion of the peelingaid substrate 402 which is not overlapped with the substrate 101 (theportion protruding outwardly from the end surface of the substrate 101).This application of the external force causes one or both of the layerto be peeled 106 and the substrate 101 to undergo a deflection. As aresult, a section of the substrate 101 peeled from the layer to bepeeled 106 is formed partially or entirely at the substrate peripherywith the peeling layer 102 exposed (see FIG. 4C).

It is to be noted that examples of the external force in the presentembodiment include, for example, a method of pressing a plate-likeobject 403 against the peeling aid substrate 402 to apply a force, asshown in FIG. 4C.

While an external force is applied to the interface between the peelinglayer 102 and the layer to be peeled 106 in Embodiment 1, the section towhich an external force is applied is not overlapped with the outline ofthe substrate 101 (protrudes outwardly from the end surface of thesubstrate 101) in the present embodiment. Thus, an external force can beapplied in a simpler way in the present embodiment. In addition, sincean external force is applied via the peeling aid substrate 402 to theinterface between the peeling layer 102 and the layer to be peeled 106,there is no need to apply an external force directly to the peelinglayer 102 and the layer to be peeled 106 (such as to press a blade witha sharp tip directly against the interface between the peeling layer 102and the layer to be peeled 106 as in FIG. 2D), and the damage to thepeeling layer 102 and the layer to be peeled 106 can be thus eliminated.

This application of an external force can peel the substrate 101 fromthe layer to be peeled 106 in a simpler way.

The implementation of this treatment can prevent cracking from beingcaused and developed at the substrate periphery with the peeling layerexposed, when the substrate 101 is peeled entirely from the layer to bepeeled 106 in the next step.

Next, with, as a starting point, the section of the substrate 101 peeledfrom the layer to be peeled 106, an external force is applied to theinterface between the peeling layer 102 and the layer to be peeled 106with the use of the peeling aid substrate 402 to peel the substrate 101wholly from the layer to be peeled 106 (see FIG. 4D).

Next, the layer to be peeled 106 with the supporting material 200 formedis separated from the fixing jig 204. After the separation, the basematerial 302 is placed on the surface of the layer to be peeled 106 withthe substrate 101 peeled therefrom, with the adhesive material 300interposed therebetween. In this state, the supporting material 200 issubjected to the adhesion-reducing treatment 304. This treatment reducesthe adhesion at the surface of the supporting material 200 in contactwith the layer to be peeled 106, thereby allowing the supportingmaterial 200 to be peeled from the layer to be peeled 106. Therefore, asin the case of FIG. 3E, a flexible semiconductor device 310 can bemanufactured.

The use of the method described above can prevent waste generation frombeing caused by peeling of films from the peeling layer 102 sectionduring the first dividing treatment. In addition, the use of the methodcan prevent failure of peeling from being caused by waste due to peelingof films from the peeling layer 102 section during the second dividingtreatment. Furthermore, the substrate 101 can be peeled from the layerto be peeled 106 in a simpler way.

Thus, a method can be provided for manufacturing a flexiblesemiconductor device in a simpler way with a high yield.

Further, the present embodiment can be appropriately combined with anyof the other embodiments described in this specification.

Embodiment 3

In the present embodiment, in connection with the method formanufacturing a semiconductor device as described in Embodiment 1, amethod will be described with reference to FIGS. 5A to 5C formanufacturing a semiconductor device with the use of a different type ofsupporting material.

In the present embodiment, the second semiconductor substrate 110 isused. The second semiconductor substrate 110 is the same as described inEmbodiment 1. On the layer to be peeled 106 of the second semiconductorsubstrate 110, a supporting material 500 is formed. Then, dividing linesare formed near the peripheral section of the substrate 101. Thedividing lines are formed in the section of the peeling layer 102 andlayer to be peeled 106 stacked. As the method for forming the dividinglines, for example, a thin blade may be brought into contact with thesection while rotating the blade at high speed, a blade with a sharp tipmay be pressed against the section, the section may be irradiated withhigh energy (for example, such as a CO₂ laser or a YAG laser beam), orthe section may be exposed to a high-pressure liquid (for example,high-pressure water). With the use of the dividing lines formed in thesubstrate 101, the section outside the dividing lines is separated fromthe substrate 101. After that, the surface of the substrate 101 with thesupporting material 500 formed is fixed in close contact with the fixingjig 204 (see FIG. 5A).

As the supporting material 500, a material is used which has closecontact force F per unit area in the range of “f1<F<f2” to the layer tobe peeled 106. It is to be noted that the parameter f1 refers to a forceper unit area for the external force applied to the interface betweenthe peeling layer 102 and the layer to be peeled 106 when the substrate101 is peeled from the layer to be peeled 106, and the parameter f2refers to an adhesive force per unit area at the interface between theadhesive material 300 and the layer to be peeled 106 when the layer tobe peeled 106 and the base material 302 are bonded to each other withthe adhesive material 300 interposed therebetween in the subsequentstep.

Next, an external force is applied to the interface between the peelinglayer 102 exposed at the end of the substrate and the layer to be peeled106. This application of the external force causes one or both of thelayer to be peeled 106 and the substrate 101 to undergo a deflection. Asa result, a section of the substrate 101 peeled from the layer to bepeeled 106 is formed partially or entirely at the substrate periphery.Furthermore, with, as a starting point, the section of the substrate 101peeled from the layer to be peeled 106, the substrate 101 is peeledwholly from the layer to be peeled 106 (see FIG. 5B).

In this case, the close contact force F (the close contact force perunit area at the interface between the supporting material 500 and thelayer to be peeled 106) is greater than the force f1 (the force per unitarea for the external force applied in order to peel the substrate 101from the layer to be peeled 106). For this reason, the substrate 101 canbe peeled selectively from the layer to be peeled 106 without thesupporting material 500 peeled from the layer to be peeled 106.

Next, the layer to be peeled 106 with the supporting material 500 formedis separated from the fixing jig 204, the base material 302 is provideon the surface of the layer to be peeled 106 with no supporting material500 formed, with the adhesive material 300 interposed therebetween, andthe supporting material 500 is peeled from the layer to be peeled 106(see FIG. 5C).

In this case, the close contact force F (the close contact force perunit area at the interface between the supporting material 500 and thelayer to be peeled 106) is less than the adhesive force f2 (the adhesiveforce per unit area at the interface between the adhesive material 300and the layer to be peeled 106). For this reason, the supportingmaterial 500 can be peeled selectively from the layer to be peeled 106without the base material 302 peeled from the adhesive material 300.

Thus, as in the case of FIG. 3E, the flexible semiconductor device 310can be manufactured where the layer to be peeled 106 with thesemiconductor circuit 104 formed therein responsible for the operationof the semiconductor device is fixed to the base material 302 with theadhesive material 300 interposed therebetween.

The method described above allows a semiconductor device to bemanufactured without carrying out any treatment for reducing the closecontact force of the supporting material.

Thus, the deterioration of the semiconductor circuit can be suppressedwhich is caused by the treatment for reducing the close contact force ofthe supporting material, thereby allowing a semiconductor device withhigh reliability to be manufactured.

Further, the present embodiment can be appropriately combined with anyof the other embodiments described in this specification.

Embodiment 4

In the present embodiment, in connection with the method formanufacturing a semiconductor device as described in Embodiment 1, amethod will be described with reference to FIGS. 6A to 6D formanufacturing a semiconductor device with the use of a different type ofsupporting material.

In the present embodiment, the second semiconductor substrate 110 isused. The second semiconductor substrate 110 is the same as described inEmbodiment 1. On the layer to be peeled 106 of the second semiconductorsubstrate 110, a supporting material 600 is formed. Then, dividing linesare formed near the peripheral section of the substrate 101. Thedividing lines are formed in the section of the peeling layer 102 andlayer to be peeled 106 stacked. As the method for forming the dividinglines, for example, a thin blade may be brought into contact with thesection while rotating the blade at high speed, a blade with a sharp tipmay be pressed against the section, the section may be irradiated withhigh energy (for example, such as a CO₂ laser or a YAG laser beam), orthe section may be exposed to a high-pressure liquid (for example,high-pressure water). With the dividing lines formed in the substrate101, the section outside the dividing lines is separated from thesubstrate 101. After that, the surface of the substrate 101 with thesupporting material 600 formed is fixed in close contact with the fixingjig 204.

As the supporting material 600, a material is used which can bedissolved and thereby removed by immersion in a solvent. Examples ofthis type of material include, for example, a water-soluble adhesivewhich can be dissolved and thereby removed by immersion in water.

Next, an external force is applied to the interface between the peelinglayer 102 exposed at the end of the substrate and the layer to be peeled106. This application of the external force causes one or both of thelayer to be peeled 106 and the substrate 101 to undergo a deflection. Asa result, the substrate 101 is peeled from the layer to be peeled 106partially or entirely at the substrate periphery. Furthermore, with, asa starting point, the section of the substrate 101 peeled from the layerto be peeled 106, the substrate 101 is peeled wholly from the layer tobe peeled 106. After that, the layer to be peeled 106 with thesupporting material 600 formed is separated from the fixing jig 204.After the separation, the base material 302 is placed on the surface ofthe layer to be peeled 106 with the substrate 101 peeled therefrom, withan adhesive material 602 interposed therebetween (see FIG. 6B).

It is to be noted that a material which exhibits insolubility to asolvent used is preferably used for the adhesive material 602, becausethe operation of immersing the supporting material 600 in the solvent topeel the supporting material 600 from the layer to be peeled 106 iscarried out in a subsequent step.

Next, the supporting material 600 and the layer to be peeled 106 withthe base material 302 placed with the adhesive material 602 interposedtherebetween are immersed in a solvent 604 to dissolve the supportingmaterial 600, thereby removing the supporting material 600 from thelayer to be peeled 106 (see FIG. 6C).

Thus, a flexible semiconductor device 610 can be manufactured where thelayer to be peeled 106 with the semiconductor circuit 104 formed thereinresponsible for the operation of the semiconductor device is fixed tothe base material 302 with the adhesive material 602 interposedtherebetween (see FIG. 6D).

The method described above allows a semiconductor device to bemanufactured without applying any physical force for peeling thesupporting material.

Thus, a high-yield and high-reliability semiconductor device can bemanufactured in which the deterioration of the semiconductor circuit issuppressed which is caused by the force applied when the supportingmaterial is peeled.

Further, the present embodiment can be appropriately combined with anyof the other embodiments described in this specification.

This application is based on Japanese Patent Application serial no.2010-144127 filed with Japan Patent Office on Jun. 24, 2010, the entirecontents of which are hereby incorporated by reference.

1. A method for manufacturing a semiconductor device, the methodcomprising the steps of: forming a plurality of island-shaped peelinglayers on a substrate; forming a first layer on the plurality ofisland-shaped peeling layers, the first layer comprising a semiconductorlayer; dividing the plurality of island-shaped peeling layers by cuttingthe first layer and the substrate at a section at which the substrateand the first layer are in contact with each other such that a pluralityof chips which each comprise the cut first layer, the cut substrate andthe divided island-shaped peeling layer is formed; attaching asupporting material on the cut first layer of one of the plurality ofchips; removing an end portion of the cut substrate of the one of theplurality of chips and an end portion of the divided island-shapedpeeling layer of the one of the plurality of chips; peeling the cutsubstrate of the one of the plurality of chips from the cut first layerof the one of the plurality of chips at a boundary between the dividedisland-shaped peeling layer of the one of the plurality of chips and thefirst layer of the one of the plurality of chips; attaching a basematerial to the first layer of the one of the plurality of chips with anadhesive material interposed therebetween; and peeling the supportingmaterial from the first layer of the one of the plurality of chips. 2.The method for manufacturing a semiconductor device according to claim1, wherein adherence of the peelable supporting material is adherencedecreased by applying a load.
 3. The method for manufacturing asemiconductor device according to claim 1, wherein as the peelablesupporting material, a material is used such that a adhesive forcebetween the supporting material and the peeled layer is stronger than aforce required for separating the substrate from the peeled layer, andthe adhesive force between the supporting material and the peeled layeris weaker than the adhesive force between the adhesive material and thepeeled layer.
 4. The method for manufacturing a semiconductor deviceaccording to claim 1, wherein a material dissolved in a solvent byimmersion in the solvent is used as the peelable supporting material. 5.A method for manufacturing a semiconductor device, the method comprisingthe steps of: forming a plurality of island-shaped peeling layers on asubstrate; forming a first layer on the plurality of island-shapedpeeling layers, the first layer comprising a semiconductor layer;dividing the plurality of island-shaped peeling layers by cutting thefirst layer and the substrate at a section at which the substrate andthe first layer are in contact with each other such that a plurality ofchips which each comprise the cut first layer, the cut substrate and thedivided island-shaped peeling layer is formed; attaching a supportingmaterial on the cut first layer of one of the plurality of chips;removing an end portion of the cut substrate of the one of the pluralityof chips and an end portion of the divided island-shaped peeling layerof the one of the plurality of chips; attaching a second substrate to asecond face of the first substrate of the divided island-shaped peelinglayer with an adhesive material interposed therebetween; peeling the cutsubstrate of the one of the plurality of chips from the cut first layerof the one of the plurality of chips at a boundary between the dividedisland-shaped peeling layer of the one of the plurality of chips and thefirst layer of the one of the plurality of chips; attaching a basematerial to the first layer of the one of the plurality of chips with anadhesive material interposed therebetween; and peeling the supportingmaterial from the first layer of the one of the plurality of chips. 6.The method for manufacturing a semiconductor device according to claim5, wherein adherence of the peelable supporting material is adherencedecreased by applying a load.
 7. The method for manufacturing asemiconductor device according to claim 5, wherein as the peelablesupporting material, a material is used such that a adhesive forcebetween the supporting material and the peeled layer is stronger than aforce required for separating the substrate from the peeled layer, andthe adhesive force between the supporting material and the peeled layeris weaker than the adhesive force between the adhesive material and thepeeled layer.
 8. The method for manufacturing a semiconductor deviceaccording to claim 5, wherein a material dissolved in a solvent byimmersion in the solvent is used as the peelable supporting material.